Accelerated Motion and Gravity Equivalence

It seems a principal of Einstein’s General Theory of Relativity that there is an equivalence between accelerated motion and being in a gravitational field. It seems that an observer would have no way to tell the difference between these two states. However, the gravitational force being mediated by elementary force carrying particles (gluons I think), couldn’t the observer establish that he was in the presence of a gravitational field by observing these gluons (or other effects like gravitational waves), effects that would presumably not be present if he was accelerating due to a jet engine for example. Or, is the ‘equivalence’ of gravity and accelerated motion only up to the observed dynamics and not other aspects of the physical world ?